1. Field of the Invention
The present invention relates to a socket for tightening a workpiece with an adjustable torque.
2. Description of Related Art
Tighteners are generally used in the industry to rapidly tighten nuts, bolts or other workpieces to a receiving part. For example, tighteners may be used to secure spark plugs in internal combustion engines. Referring to FIG. 1, a conventional spark plug tightener 1 conventionally includes an elongated body 2 having a bottom end surface 3 in which a hole is formed with a hexagonal portion. In use, the hexagonal portion of the hole is engaged within the hexagonal casing 4 of the spark plug 5 and the rotation of the elongated body drives and secures the spark plug within the cylinder cover of the engine 6. Rotation of the elongated body 2 may be done manually with a shaft 7 that is passed through the upper portion 8 of the elongated body 2.
Generally, it is desirable to control the transmitted torque for properly securing the workpiece (e.g., the spark plug) to the receiving part (e.g., the engine). The workpiece should not be secured too tightly to ensure that the threads or the holding elements of the receiving part are not fractured or weakened, or that the workpiece is not damaged. Similarly, the workpiece should not be secured too loosely. In order to control the applied torque and to prevent the workpiece from being damaged during tightening, tighteners having a preset amount of torque may be used. Upon reaching that preset amount of torque, the tightener may be arranged to release and spin freely. Alternatively, or in addition, the tightener may include a device to create an audible sound when the torque for which it is set is reached. In this latter configuration, though, the tightener may not completely prevent the user from applying more torque after the signal is given. However, conventional tighteners having a preset amount of torque are generally expensive, heavy and difficult to use in tight environments such as that of many engines. As a result, simpler tools are used in current automotive repair environments and the degree of tightening of many workpieces, such as spark plugs, is left for the most part to the judgment of the user.